Eight solar panels and one measly little wind generator supplied all the power we used. We bolted the pole that supported the wind generator to a wall of our house, which, sound-wise, turned the roof of the house into one big drumhead.  Oops! Live and learn. And when the wind REALLY blew—which was often—the thing broke. The manufacturer replaced the main unit several times before we gave up on wind power.
Usually however, renewable energy is derived from the mains electricity grid. This means that energy storage is mostly not used, as the mains electricity grid is organised to produce the exact amount of energy being consumed at that particular moment. Energy production on the mains electricity grid is always set up as a combination of (large-scale) renewable energy plants, as well as other power plants as fossil-fuel power plants and nuclear power. This combination however, which is essential for this type of energy supply (as e.g. wind turbines, solar power plants etc.) can only produce when the wind blows and the sun shines. This is also one of the main drawbacks of the system as fossil fuel powerplants are polluting and are a main cause of global warming (nuclear power being an exception). Although fossil fuel power plants too can be made emissionless (through carbon capture and storage), as well as renewable (if the plants are converted to e.g. biomass) the best solution is still to phase out the latter power plants over time. Nuclear power plants too can be more or less eliminated from their problem of nuclear waste through the use of nuclear reprocessing and newer plants as fast breeder and nuclear fusion plants.
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Julia Pyper is a Senior Editor at Greentech Media covering clean energy policy, the solar industry, grid edge technologies and electric mobility. She previously reported for E&E Publishing, and has covered clean energy and climate change issues across the U.S. and abroad, including in Haiti, Israel and the Maldives. Julia holds degrees from McGill and Columbia Universities. Find her on Twitter @JMPyper.
While a single dramatic victory against something like the dirty Keystone XL pipeline can be nice to imagine, the truth is this is how we’re going to win: fighting at every level and with every tool we’ve got. We can’t stop until governments and fossil fuel corporations finally get the message that we need to put our dirty past behind us and fully commit to a clean future that works for all of us moving forward. 

One- to 10-kW turbines can be used in applications such as pumping water. Wind energy has been used for centuries to pump water and grind grain. Although mechanical windmills still provide a sensible, low-cost option for pumping water in low-wind areas, farmers and ranchers are finding that wind-electric pumping is more versatile and they can pump twice the volume for the same initial investment. In addition, mechanical windmills must be placed directly above the well, which may not take advantage of available wind resources. Wind-electric pumping systems can be placed where the wind resource is the best and connected to the pump motor with an electric cable. However, in areas with a low wind resource, mechanical windmills can provide more efficient water pumping.

In a twist that has some Republicans in this oil- and gas-rich state whistling Dixie, Ross is now friends with Al Gore, who featured Ross in An Inconvenient Sequel, the 2017 follow-up to An Inconvenient Truth, his Oscar-winning documentary about global warming. “We bonded right away,” Ross recalls. “I said, ‘Mr. Vice President, we’ve got a lot in common. You invented the internet. I invented green energy.’” Trained as an accountant, Ross still works as one—being mayor of Georgetown is a part-time job—and there’s no mistaking his zeal for the other kind of green. When conservatives complain about his energy politics, he is quick to remind them that the city has the lowest effective tax rate in Central Texas.

The use of a gearbox allows for better matching of the generator speed to that of the turbine but the disadvantage of using a gearbox is that as a mechanical component it is subjected to wear and tear reducing the efficiency of the system. Direct drive however may be more simple and efficient, but the generators rotor shaft and bearings are subjected to the full weight and rotational force of the rotor blades.
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This items including : 2pcs 400W wind turbine with grid tie controller ,2pcs waterproof grid tie inverter ! Why Off Grid Systems Should Include Wind? Wind provides power at night. Wind is strongest during the winter months when solar resources are limited. Wind provides power during poor weather conditions. Air density is higher in colder weather and maximizes power production.
The home wind Generator systems are designed for reliable power output for the next 30 years or so. With every price increase of the utility company power your investment gets better all the time. Utility costs are rising all over and will accelerate over the next few years. We expect the cost of electricity to rise and double over Obamas term in office due to cap and trade and increased regulation and market pressure.
“New Wind May Be Cheaper than Old, Reliable Coal” • Wind farms have cost less to build and operate than coal-fired power plants for some time. The trend of lower costs for renewables has crossed a threshold: it is sometimes cheaper to build a brand new wind facility than keep an old coal plant burning, according to Lazard Ltd. [Casper Star-Tribune Online]
Cleaner air and water: Burning fossil fuels releases greenhouse gases (GHG) into the atmosphere. GHG contribute to global climate change, rising sea levels and unpredictable weather patterns that can be costly in terms of human and economic losses. Burning fossil fuels also releases contaminants in to the air and water near the power generation source. Alternative energy sources can produce the same electricity in a greener way. You can shrink your carbon footprint, help curb climate change and reduce air and water pollution when you choose renewable electricity.
Current Texas solar incentives include generous rebates for solar electric and solar hot water systems.  When combined with Federal solar rebates your solar panel installation will be approximately 50% less because of the incentives!  Our solar installers will be happy to answer your questions and explain the benefits of solar power.  Simply click the image below, fill in the form, and a certified solar installer will contact you by phone at your convenience.
In 2010, the International Energy Agency predicted that global solar PV capacity could reach 3,000 GW or 11% of projected global electricity generation by 2050—enough to generate 4,500 TWh of electricity.[40] Four years later, in 2014, the agency projected that, under its "high renewables" scenario, solar power could supply 27% of global electricity generation by 2050 (16% from PV and 11% from CSP).[2]
Materials that are typically used for the rotor blades in wind turbines are composites, as they tend to have a high stiffness, high strength, high fatigue resistance, and low weight.[46] Typical resins used for these composites include polyester and epoxy, while glass and carbon fibers have been used for the reinforcing material.[47] Construction may use manual layup techniques or composite resin injection molding. As the price of glass fibers is only about one tenth the price of carbon fiber, glass fiber is still dominant.

“[The maps] suggest that our 100 percent renewable energy purchasing goal — which relies on buying surplus renewable energy when it’s sunny and windy, to offset the lack of renewable energy supply in other situations — is an important first step toward achieving a fully carbon-free future,” Michael Terrell, Google’s head of energy markets, wrote in a blog post. “Ultimately, we aspire to source carbon-free energy for our operations in all places, at all times.”
Several refineries that can process biomass and turn it into ethanol are built by companies such as Iogen, POET, and Abengoa, while other companies such as the Verenium Corporation, Novozymes, and Dyadic International[163] are producing enzymes which could enable future commercialization. The shift from food crop feedstocks to waste residues and native grasses offers significant opportunities for a range of players, from farmers to biotechnology firms, and from project developers to investors.[164]
Which is to say that Ross and his co-workers had options. And the city was free to take advantage of them because of a rather unusual arrangement: Georgetown itself owns the utility company that serves the city. So officials there, unlike those in most cities, were free to negotiate with suppliers. When they learned that rates for wind power could be guaranteed for 20 years and solar for 25 years, but natural gas for only seven years, the choice, Ross says, was a “no-brainer.”
While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas and developing countries, where energy is often crucial in human development.[13] Former United Nations Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity.[14] As most of renewables provide electricity, renewable energy deployment is often applied in conjunction with further electrification, which has several benefits: Electricity can be converted to heat (where necessary generating higher temperatures than fossil fuels), can be converted into mechanical energy with high efficiency and is clean at the point of consumption.[15][16] In addition to that electrification with renewable energy is much more efficient and therefore leads to a significant reduction in primary energy requirements, because most renewables don't have a steam cycle with high losses (fossil power plants usually have losses of 40 to 65%).[17]
Similarly, in the United States, the independent National Research Council has noted that "sufficient domestic renewable resources exist to allow renewable electricity to play a significant role in future electricity generation and thus help confront issues related to climate change, energy security, and the escalation of energy costs … Renewable energy is an attractive option because renewable resources available in the United States, taken collectively, can supply significantly greater amounts of electricity than the total current or projected domestic demand."[154]

Common battery technologies used in today's home PV systems include, the valve regulated lead-acid battery– a modified version of the conventional lead–acid battery, nickel–cadmium and lithium-ion batteries. Lead-acid batteries are currently the predominant technology used in small-scale, residential PV systems, due to their high reliability, low self discharge and investment and maintenance costs, despite shorter lifetime and lower energy density. However, lithium-ion batteries have the potential to replace lead-acid batteries in the near future, as they are being intensively developed and lower prices are expected due to economies of scale provided by large production facilities such as the Gigafactory 1. In addition, the Li-ion batteries of plug-in electric cars may serve as a future storage devices in a vehicle-to-grid system. Since most vehicles are parked an average of 95 percent of the time, their batteries could be used to let electricity flow from the car to the power lines and back. Other rechargeable batteries used for distributed PV systems include, sodium–sulfur and vanadium redox batteries, two prominent types of a molten salt and a flow battery, respectively.[114][115][116]

A Darrieus type vertical axis wind turbine (the egg-beater type) can in theory work almost as good as a horizontal axis turbine. Actual measurement of one of the better designs out there, the UGE VisionAir5, does not bear that out though: It measures in at a pitiful 11% efficiency at 11 m/s wind speed, while a Bergey Excel-6 HAWT clocks in at 22% efficiency for that same wind speed, twice as much. You can read about it in Paul Gipe’s article.  Besides efficiency issues, a Darrieus VAWT unfortunately has a number of inherent issues that put them at a disadvantage: Since they are usually tall and relatively narrow structures the bending forces on their main bearing (at the bottom) are very large. There are similar issues with the forces on the blades. This means that to make a reliable vertical axis turbine takes more material, and more expensive materials, in comparison to a horizontal type turbine. For comparison, that same UGE VisionAir5 weighs 756 kg vs. the Bergey Excel-6 at 350 kg. Keep in mind that the UGE turbine only sweeps about half the area of the Bergey, the latter is a much larger turbine! This makes VAWTs inherently more expensive, or less reliable, or both.


In an electricity system without grid energy storage, generation from stored fuels (coal, biomass, natural gas, nuclear) must be go up and down in reaction to the rise and fall of solar electricity (see load following power plant). While hydroelectric and natural gas plants can quickly follow solar being intermittent due to the weather, coal, biomass and nuclear plants usually take considerable time to respond to load and can only be scheduled to follow the predictable variation. Depending on local circumstances, beyond about 20–40% of total generation, grid-connected intermittent sources like solar tend to require investment in some combination of grid interconnections, energy storage or demand side management. Integrating large amounts of solar power with existing generation equipment has caused issues in some cases. For example, in Germany, California and Hawaii, electricity prices have been known to go negative when solar is generating a lot of power, displacing existing baseload generation contracts.[107][108]

Climate change and global warming concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization.[10] New government spending, regulation and policies helped the industry weather the global financial crisis better than many other sectors.[24] According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world's electricity within 50 years, reducing the emissions of greenhouse gases that harm the environment.[25]


Concentrating solar power plants with wet-cooling systems, on the other hand, have the highest water-consumption intensities of any conventional type of electric power plant; only fossil-fuel plants with carbon-capture and storage may have higher water intensities.[135] A 2013 study comparing various sources of electricity found that the median water consumption during operations of concentrating solar power plants with wet cooling was 810 ga/MWhr for power tower plants and 890 gal/MWhr for trough plants. This was higher than the operational water consumption (with cooling towers) for nuclear (720 gal/MWhr), coal (530 gal/MWhr), or natural gas (210).[134] A 2011 study by the National Renewable Energy Laboratory came to similar conclusions: for power plants with cooling towers, water consumption during operations was 865 gal/MWhr for CSP trough, 786 gal/MWhr for CSP tower, 687 gal/MWhr for coal, 672 gal/MWhr for nuclear, and 198 gal/MWhr for natural gas.[136] The Solar Energy Industries Association noted that the Nevada Solar One trough CSP plant consumes 850 gal/MWhr.[137] The issue of water consumption is heightened because CSP plants are often located in arid environments where water is scarce.
Join GTM at the upcoming Power & Renewables Summit! We'll cover how decarbonization, sector electrification and shifting regulatory developments will transform power markets over the next 10-to-20 years. We have already confirmed senior executives with FERC, Exelon, ERCOT, PJM, APS, Microsoft, Dell, CPS Energy, NRG, CohnReznick, Los Angeles Department of Water & Power and many more. Learn more here.
List of onshore wind farms List of onshore wind farms in the United Kingdom List of offshore wind farms in the United Kingdom List of offshore wind farms in the United States Lists of offshore wind farms by country Lists of offshore wind farms by water area Lists of wind farms by country List of wind farms in Australia List of wind farms in Canada List of wind farms in Iran List of wind farms in New Zealand List of wind farms in Romania List of wind farms in Sweden List of wind farms in the United States List of wind turbine manufacturers
Consumers throughout the United States have a third green power option: Renewable Energy Certificates (RECs or sometimes "green tags"). A REC represents the environmental attributes or benefits of renewable electricity generation (usually one credit = one kilowatt-hour). RECs can be purchased in almost any quantity and are usually available from someone other than your electricity provider. What you pay for is the benefit of adding clean, renewable energy generation to the regional or national electricity grid. The overall environmental benefit of purchasing a green pricing or green marketing product versus RECs is exactly the same. RECs provide a "green" option for people in any state, but are ideal for people who live in states where green pricing and green marketing options are not available. 
Many of the largest operational onshore wind farms are located in the USA and China. The Gansu Wind Farm in China has over 5,000 MW installed with a goal of 20,000 MW by 2020. China has several other "wind power bases" of similar size. The Alta Wind Energy Center in California is the largest onshore wind farm outside of China, with a capacity of 1020 MW of power.[141] Europe leads in the use of wind power with almost 66 GW, about 66 percent of the total globally, with Denmark in the lead according to the countries installed per-capita capacity.[142] As of February 2012, the Walney Wind Farm in United Kingdom is the largest offshore wind farm in the world at 367 MW, followed by Thanet Wind Farm (300 MW), also in the UK.
Al Gore says the reason is innovation. “The cost-reduction curve that came to technologies like computers, smartphones and flat-panel televisions has come to solar energy, wind energy and battery storage,” he says. “I remember being startled decades ago when people first started to explain to me that the cost of computing was being cut in half every 18 to 24 months. And now this dramatic economic change has begun to utterly transform the electricity markets.”

Concentrated solar power plants may use thermal storage to store solar energy, such as in high-temperature molten salts. These salts are an effective storage medium because they are low-cost, have a high specific heat capacity, and can deliver heat at temperatures compatible with conventional power systems. This method of energy storage is used, for example, by the Solar Two power station, allowing it to store 1.44 TJ in its 68 m³ storage tank, enough to provide full output for close to 39 hours, with an efficiency of about 99%.[110]
Geothermal energy is produced by tapping into the thermal energy created and stored within the earth. It arises from the radioactive decay of an isotope of potassium and other elements found in the Earth's crust.[144] Geothermal energy can be obtained by drilling into the ground, very similar to oil exploration, and then it is carried by a heat-transfer fluid (e.g. water, brine or steam).[144] Geothermal systems that are mainly dominated by water have the potential to provide greater benefits to the system and will generate more power.[145] Within these liquid-dominated systems, there are possible concerns of subsidence and contamination of ground-water resources. Therefore, protection of ground-water resources is necessary in these systems. This means that careful reservoir production and engineering is necessary in liquid-dominated geothermal reservoir systems.[145] Geothermal energy is considered sustainable because that thermal energy is constantly replenished.[146] However, the science of geothermal energy generation is still young and developing economic viability. Several entities, such as the National Renewable Energy Laboratory[147] and Sandia National Laboratories[148] are conducting research toward the goal of establishing a proven science around geothermal energy. The International Centre for Geothermal Research (IGC), a German geosciences research organization, is largely focused on geothermal energy development research.[149]
Marine energy (also sometimes referred to as ocean energy) refers to the energy carried by ocean waves, tides, salinity, and ocean temperature differences. The movement of water in the world's oceans creates a vast store of kinetic energy, or energy in motion. This energy can be harnessed to generate electricity to power homes, transport and industries. The term marine energy encompasses both wave power – power from surface waves, and tidal power – obtained from the kinetic energy of large bodies of moving water. Reverse electrodialysis (RED) is a technology for generating electricity by mixing fresh river water and salty sea water in large power cells designed for this purpose; as of 2016 it is being tested at a small scale (50 kW). Offshore wind power is not a form of marine energy, as wind power is derived from the wind, even if the wind turbines are placed over water. The oceans have a tremendous amount of energy and are close to many if not most concentrated populations. Ocean energy has the potential of providing a substantial amount of new renewable energy around the world.[165]
Biomass is biological material derived from living, or recently living organisms. It most often refers to plants or plant-derived materials which are specifically called lignocellulosic biomass.[65] As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods. Wood remains the largest biomass energy source today;[66] examples include forest residues – such as dead trees, branches and tree stumps –, yard clippings, wood chips and even municipal solid waste. In the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bamboo,[67] and a variety of tree species, ranging from eucalyptus to oil palm (palm oil).
Worldwide growth of photovoltaics has averaged 40% per year from 2000 to 2013[35] and total installed capacity reached 303 GW at the end of 2016 with China having the most cumulative installations (78 GW)[36] and Honduras having the highest theoretical percentage of annual electricity usage which could be generated by solar PV (12.5%).[36][35] The largest manufacturers are located in China.[37][38]
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